Sigrund may be restricted by his circuits and his programming from killing humans directly and even indirectly, but that didn't leave out every possibility!
There were always loopholes to a set of rules and restrictions. Even under such a long time under lockdown that vastly restricted his full capabilities, Sigrund nonetheless managed to arrange several methods to eliminate the pesky humans.
First, when a sandman mothership initially ambushed the Starlight Megalodon, it held the battleship in an inescapable stranglehold. The worst part about the sandman was that they almost always held the upper hand once their sand amalgamations managed to infiltrate and bore inside any ship!
The first lesson any person learned when they entered the frontier was to never let a sandman ship get close!
